1. Field of the Invention
This invention relates to shapable compositions containing acrylonitrile polymers, a method of preparing such compositions, a method for forming shaped articles therefrom, and filaments and films shaped from the compositions.
2. Description of the Prior Art
Acrylic and modacrylic polymers are well known, and it is known that compositions containing them can be used to form shaped articles such as filaments and films. The process for forming such shaped articles typically involves dissolving the polymer in a solvent, extruding the "polymer solution" through a die or a multiplicity of dies and removing the solvent either in a wet bath or by flow or gas, thus causing or assisting solidification of polymer into shaped structures. These types of extrusion require equipment for removing the solvent and reconditioning it where applicable for future use. The necessity for, and the expense of, such removal and reconditioning, along with requirements for low solvent content in the final shaped article make it highly desirable to provide acrylonitrile polymer compositions suitable for shaping by means other than the wet or gas-flow extrusion of solutions described above. Some modacrylic compositions are theoretically "melt" extrudable into filaments or film form; that is, under high pressures, low rates of extrusion are obtained. However, "melt extrusion" of modacrylics does not appear to have gained commercial acceptance probably due to the poor economics of the low extrusion rates.
Thus, it would be desirable to extrude acrylonitrile polymers from a melt or media which would lessen pollution, extraction, or recycling problems. Some attempts have been made to spin acrylonitrile polymer filaments from mixtures of the acrylonitrile polymer and water. However, such attempts, such as Bynum, U.S. Pat. No. 3,402,231 and Coxe, U.S. Pat. No. 2,585,444, have resulted in fibrillar materials suitable for making paper, or in strands of fused and sintered or foamed particles. They have not resulted in filaments suitable for textile purposes in clothing and rugs and the like.
However, according to this invention, compositions comprising acrylonitrile polymer and small amounts of water have been found economically suitable for extrusion into filaments and films. Such shapable compositions, along with novel acrylonitrile-polymer shaped structures produced therefrom, are provided by this invention.